1. Technical Field of the Invention
The invention relates to the field of chemical separation and more particularly to a method and apparatus for acoustophoresis, i.e., the separation of species via acoustic waves.
2. Description of the Related Art
Prior methods of species separation depend for the most part on gravity, with the separation depending on material density. Artificially high gravity gradients achieved by centrifuging can separate very small differences in density. Solubility, freezing, and boiling are also processes for separation, with each depending on a specific physical/chemical property to achieve the separation. Another process is electrophoresis, which produces a chemical separation based on the interaction of the species with an electric field. Each of these methods is unable to separate species with similar separation properties key for the particular method. Freezing and boiling separation may also damage the chemical or solid species or change their properties. In addition, high gravity techniques are expensive and rather complex.
Prior separation techniques involving acoustic or sonic energy have relied on either intense acoustic standing waves and associated migration or direct reflection related forces at planar interferences, not acoustic absorption or radiation pressure characteristics.